Tenofovir disoproxil fumarate has not been evaluated in patients receiving nephrotoxic medicinal products (e.g. aminoglycosides, amphotericin B, foscarnet, ganciclovir, pentamidine, vancomycin, cidofovir or interleukin-2). Use of tenofovir disoproxil fumarate should be avoided with concurrent or recent use of a nephrotoxic medicinal product. If concomitant use of tenofovir disoproxil fumarate and nephrotoxic agents is unavoidable, renal function should be monitored weekly. Tenofovir disoproxil fumarate has not been clinically evaluated in patients receiving medicinal products which are secreted by the same renal transporter, human organic anion transporter 1 (hOAT1) (e.g. cidofovir, a known nephrotoxic medicinal product). This renal transporter (hOAT1) may be responsible for tubular secretion and in part, renal elimination of tenofovir, adefovir and cidofovir. Consequently, the pharmacokinetics of these medicinal products might be modified if they are co-administered. In healthy volunteers, a single dose of adefovir dipivoxil given with tenofovir disoproxil fumarate did not result in a relevant drug-drug interaction with regard to pharmacokinetics. However, the clinical safety including potential renal effects of the co-administration of adefovir dipivoxil and tenofovir disoproxil fumarate is unknown. Unless clearly necessary, concomitant use of these medicinal products is not recommended, but if such use is unavoidable, renal function should be monitored weekly.
Viread Summary of Product Characteristics, Gilead Sciences Ltd, September 2016.

Tenofovir-DF should be avoided with concurrent or recent use of a nephrotoxic agent. Since tenofovir-DF is primarily eliminated by the kidneys, coadministration of tenofovir-DF with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of tenofovir and/or increase the concentrations of other renally eliminated drugs. Some example include, but are not limited to cidofovir, aciclovir, valaciclovir, ganciclovir and valganciclovir.
Viread Prescribing Information, Gilead Sciences International Inc, February 2016.